Jobs and Internships will be live for 30 days, and Volunteer Opportunities will be live for 6 months.
You can always hide a listing before its expiration date passes; or you can repost a new copy of a listing (but in the case of jobs and internships posted by U.S.-based organizations, you'll be charged again).
Please note that if you are posting on behalf of a recruitment firm or consultant you may only post jobs or internships. If you are posting as the administrator of a nonprofit or government organization, then you may post volunteer opportunities.